Balance calories with exercise.

Kids should get 60 minutes of moderate to vigorous play or physical activity each day. Limiting their “screen time” (i.e., watching TV, playing video games, e-mailing and instant-messaging) to two hours each day will help accomplish this goal. The number of “discretionary calories” (those spent on “extras” once nutrient needs are met) varies greatly between sedentary and active kids. Kids who are active have a discretionary-calorie allowance of about 200 to 500 calories a day, whereas sedentary kids only have 100 to 150—about the amount in an 8-ounce juice box or a handful of pretzels.